step 1:take backup of the phone using twrp and titanium backup of your oneplus one

step 2:copy the twrp,titanium backup folder,pictures ,music etc from your oneplus to the system as this method formats ur internal memory

step 3:enable adb debugging on oneplus one from the developer options (to enable developer options go to settings,then about ,and keep tapping on the build date 8 times to enable developer options)

step 4:install drivers and adb,fastboot commands for oneplus win 8: 1:install the samsung drivers 2:restart the system 3:from start,search for device manager and open it and right click on the android device and click on update drivers and inside that click on browse my computer for driver software, then click on let me pick from a list,and the select samsung android phone to install the drivers 4:install minimal adb fastboot installer and copy 4 files adb.exe,fastboot.exe,adbwinapi.dll,adbwinusbapi.dll and copy them from "C:\Program Files (x86)\Minimal ADB and Fastboot" to download location of zip file and the extracted folder win 7: 1:open the adbdriverinstaller.exe 2:select the oneplus device from manufacturere list 3:click on install driver 4:install 15 seconds adb installer and install adb and fastboot as a sytem wide command

step 5:check if ur adb is working by fiving the command "adb devices" and authorize the oneplus adb connection on the phone

NOTE:To open command prompt at the desired location,hold shift key one the keyboard and press the right key one the mouse over the location of the folder directory and then click open command window here